- Overview - Mercury Releases from Dental

Transcription

1 - Overview - Mercury Releases from Dental Mercury Amalgam to the Environment Cemetery Crematorium Dental clinic Peter Maxson Peter Maxson Concorde East/West Sprl Concorde East/West Sprl - Brussels Hg recycling Solid waste treatment Dental Sector as a Source of Mercury Incineration Contamination Workshop organised by: European Environmental Bureau - EEB Health fillings& Environment Alliance - HEAL Zero Mercury Working Group Mercury amalgam Wastewater treatment Sludge waste Goethe Institute, Brussels May 2007 Land disposal Methyl mercury Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater

2 Aaaaaaaaaaaaaaaaah!! Slide 2

3 Dental mercury study* Slide 3 Summarize key problems Scope focus on environmental releases Mercury pathways to the environment EU-27 dental mercury mass balance Conversion to methylmercury (bioavailability) Benefits vs. cost of phase-out Observations * Ref. Mercury in Dental Use, Maxson, 2007.

4 Dental mercury amalgam apparent problems Slide 4 Annual mercury use is significant Eventually most mercury is lost to the environment, and releases are very diffuse Controlling releases is costly Transformation to methylmercury Member states have very different policies with regard to dental mercury use Good candidate for Hg use reduction? P. Maxson - Concorde East/West Sprl - Brussels - concorde.ew@tele2allin.be - 25 May 2007

5 Global mercury used in dental sector Slide 5 Global mercury demand (2005) Metric tonnes Small-scale/artisanal gold mining 650-1,000 Vinyl chloride monomer (VCM) production Chlor-alkali production Batteries Dental use Measuring and control devices Lighting Electrical and electronic devices Other (paints, laboratory, pharmaceutical, cultural/traditional uses, etc.) Total 3,000-3,900 Note: In each of these sectors some mercury recycling takes place, involving the recovery of mercury from products or wastes. Therefore, net consumption of mercury in any of these sectors may be significantly lower than gross consumption indicated here.

6 EU-25 (+2) mercury used in dental sector Slide EU-25 mercury consumption (tonnes) Electrical & electronic, 35 Other uses, 30 Small-scale gold mining, 5 Lighting, 35 Measuring and control, 35 Dental amalgam, 90 Batteries, 20 Chlor-alkali, 190

7 Where does dental mercury go? Slide 7 Mercury Crematorium Dental clinic Hg recycling Cemetery Solid waste treatment Incineration Mercury amalgam fillings Sludge waste Land disposal Methyl mercury Wastewater treatment Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater, Soil, Groundwater P. Maxson - Concorde East/West Sprl - Brussels - concorde.ew@tele2allin.be - 25 May 2007

8 Simplified dental waste flow diagram Slide 8 Hg Waste Separator Waste Sewer system Sewage sludge Incineration Hg Landfill Land application Burial Cremation Courtesy of KemI Kemikalieinspektionen

9 A look at the numbers for EU-27 p1 Slide 9 Approximately 500M citizens 50-75% of persons have fillings Average mouth with fillings 3-4g mercury Human inventory t mercury fairly stable

10 A look at the numbers for EU-27 p2 Slide 10 Average filling lasts yr Annual mercury placed in fillings 100 t, not including 10-30% carved away as waste 125 t total mercury demand by dental profession Average fillings of dead person 3g mercury increasing EU cremation rate 35% increasing

11 EU-27 cremations vs. burials + trend Slide 11 Thousands 5000 Burials Cremations % 28.8% 32.7% 36.9%

12 MB 1 EU dental clinic waste mercury Slide 12 New dental mercury introduced N.B.: The mercury flows represented in this diagram are the outputs of a simple mass balance model based on inputs that often represent considerable uncertainty. The indicated flows should therefore be considered as no more than rough estimates of the actual situation EU-27 dental mercury inventory in human mouths Jan Dec2006 Dental waste including: - new amalgam waste - excavation of old amalgam Dental mercury at time of cremation Dental mercury at time of burial Lost and removed teeth P. Maxson - Concorde East/West Sprl - Brussels - concorde.ew@tele2allin.be - 25 May 2007 Traps & filters Separators Atmosphere Municipal solid waste Municipal wastewater 97

13 MB 2 dental mercury in EU MSW Atmosphere 14% Slide 13 Surface water 5% Landfill and other 70% Soil 35% Atmosphere 1% Groundwater Atmosphere Municipal solid waste 9% Surface water 27% 100% of Hg content 1% Land dispersal Surface water Wastewater sludges 4% Soil 9% 7% 5% Landfill Soil 3% Groundwater 52% 0% Groundwater Atmosphere 12% 8% Atmosphere Incineration 5% 30% Land dispersal Surface water 8% 3% Ash & flue gas residues 23% Landfill Soil 15% 12% Groundwater 2% P. Maxson - Concorde East/West Sprl - Brussels - concorde.ew@tele2allin.be - 25 May 2007

14 MB 3 EU disposal/environmental media matrix for dental Hg Slide 14 Clinic wastewater to air Municipal solid waste Municipal wastewater system Biomedical waste Hazardous waste & retirement Recycling Burial Cremation Atmosphere 100% 30% 10% 25% 2% 2% 0% 80% Surfacewater 0% 10% 40% 5% 0% 0% 0% 0% Groundwater 0% 10% 20% 5% 0% 0% 20% 0% Soil 0% 50% 30% 15% 0% 2% 80% 20% Recycled, retired, not bioavailable 0% 0% 0% 50% 98% 96% 0% 0%

15 MB 4 environ. destinations of EU dental Hg Dental waste including: 11 - new amalgam waste - excavation of old amalgam - lost teeth with amalgam 6 22 Atmosphere Municipal solid waste Municipal wastewater Biomedical waste Hazardous waste & retirement Recycling 109 Mercury releases Mercury released to: 9 potentially 63 bioavailable Slide 15 7 Soil 23 Atmosphere 2 Groundwater 14 Surface water 10 Groundwater 5 30 Soil Mercury released to: 4 Air 1 Soil P. Maxson - Concorde East/West Sprl - Brussels - concorde.ew@tele2allin.be - 25 May 2007 Mercury releases not bioavailable Sequestered, 23 retired Recycled, 22 recovered 46

16 Dental mercury and bioavailability Slide 16 Ekroth (1978) demonstrated that Hg from dental amalgam in water was taken up by fish Heintze et al. (1983) found that oral bacteria are able to methylate Hg from dental amalgams Leistevuo et al. (2001) found a correlation between the total amalgam surfaces and organic mercury in saliva Leistevuo et al. (2002) showed that the concentration of total mercury in saliva (and Hg to municipal wastewater) increased with the number of fillings Kennedy (2003) confirmed concentrations of mercury in fish increased by 200+ times in the presence of dental amalgam in the water Stone et al. (2005) observed environmentally important levels of methylmercury in dental-unit wastewater at concentrations that are orders of magnitude higher than in nature

17 Cost of controlling dental mercury releases Activity Place and year Cost a (US$ kg -1 Hg) Reduction potential Slide 17 Reference Increase recycling of mercury captured by chairside traps in dentistry Use amalgam separators at dental practices Remove amalgam fillings before burial or cremation Remove mercury from crematoria gases (warm start furnace) Scrub flue gases of medical waste incinerators Use carbon injection in flue gases of waste incinerators Use combined technologies on waste incinerators Minnesota, estimated 1999 USA, estimated 2002 Sweden, estimated 2004 OSPAR estimate USA estimated 1996 USA, estimated 1996 Uppsala, Sweden, Medium to P. Maxson - Concorde East/West Sources: Minor Sprl adaptation - Brussels of Hylander - concorde.ew@tele2allin.be and Goodsite (2006) May 2007 Medium/ Large 400 Large to to to Medium/ Large Medium/ Large Medium/ Large Large Jackson et al Derived from Bender 2002 Hylander and Goodsite 2006 Derived from OSPAR 2003a US EPA 1997 US EPA 1997 Hylander and Goodsite 2006

18 Observations p1 Uncertainty in quantities of dental mercury moving through the EU waste stream must be noted, but important conclusions may be drawn: Slide 18 Annual EU-27 mercury use is significant and higher than we thought Eventually most dental mercury is released to the environment: >20 t to the atmosphere? t to surface waters t to groundwater and soil

19 Observations p2 Slide 19 Mercury releases are very diffuse difficult and expensive to adequately control Transformation of (how much?) dental mercury to methylmercury, which may enter the food chain, especially via fish consumption Low level of awareness among many dental staff members of mercury hazards in the workplace

20 Observations p3 Slide 20 Alternatives to amalgam exist less than 5% of fillings placed in Sweden are Hg amalgam The ONLY viable (and cost-effective) response to all of these challenges is the phase-out of mercury use in dentistry